What Size Fuses/Breakers Should be Used when Adding a Second Battery and Hidden Power Battery Mount

Published 01/17/2018

Products Featured in This Question

TorkLift HiddenPower Under-Vehicle Battery Mount with Battery Box

(16)

$231.99

Deka Battery Isolator - 120 Amp

(47)

$107.07

Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded

(13)

$33.90

Pollak Circuit Breaker - Cycling/Automatic Reset - 40 Amp - Straight Mount Bracket

(49)

$7.40

Question:

In regards to the Torklift hidden power battery installation, I noticed that your installation video does not install fuses on either side of the batteries. The HiddenPower harness has 25a fuses in it but I’ve heard that I should put at least 80a in and have seen people put up to 150a in. With all the inconsistencies in these set ups, what would you recommend? Thanks

asked by: Tom

Expert Reply:

Provided that the fuses you want to install are rated for the amount of power that will be running to/from the battery you will be good to go. If you were to use fuses or breakers that are rated higher then that could allow for an overload condition before a fuse blows or a breaker trips.

It also depends on how you have it set up. If the second battery is being fed from the main battery then you wouldn't need to have a high-rated fuse or breaker. If the alternator is feeding it then you would need to look at how much power the alternator puts out.

If the battery is being used for 12 volt power to a trailer then on the output side you would want a 40 amp fuse or breaker such as # PK54540.

In the video I have linked our installer is also putting in a battery isolation solenoid, # PK5231201, which is rated for 80 amps. If you wanted you could go to a higher rated isolator such as # DW08771 rated for 120 amps.

expert reply by: Michael H